PCB optical isolation by nonuniform catch pad stack

ABSTRACT

A Printed Circuit Board (PCB) includes a via extending through at least one layer of the PCB. The PCB may also include a first catch pad connected to the via and located within a first metal layer of the PCB. The first catch pad may have a first size. The PCB may further include a second catch pad connected to the via and located within a second metal layer of the PCB. The second catch pad may have a second size greater than the first size. The second catch pad may overlap horizontally with a portion of a metallic feature in the first metal layer to obstruct light incident on a first side of the PCB from transmission to a second side of the PCB through a region of dielectric material near the via.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a continuation application of U.S. patentapplication Ser. No. 16/204,882 filed on Nov. 29, 2018 and titled “PCBOptical Isolation By Nonuniform Catch Pad Stack,” which claims priorityto U.S. patent application Ser. No. 15/613,580 filed on Jun. 5, 2017 andtitled “PCB Optical Isolation By Nonuniform Catch Pad Stack,” each ofwhich is herein incorporated by reference as if fully set forth in thisdescription.

BACKGROUND

A Printed Circuit Board (PCB) mechanically supports and electricallyconnects electronic components by way of conductive tracks, pads, vias,and other metallic features disposed on (i.e., above or beneath) andbetween a non-conductive substrate. Components such as resistors,capacitors, and active semiconductor devices are generally soldered tothe PCB, but may also be embedded directly in the substrate. A PCB canbe single sided (i.e., including only one metal layer), double sided(i.e., including two metal layers), or multi-layered (i.e., includingmultiple metal layers). Metallic features in different metal layers ofthe PCB may be electrically connected by way of vias.

SUMMARY

In an example embodiment, a Printed Circuit Board (PCB) may havenon-uniformly sized via catch pads that overlap with or interposebetween metallic features in adjacent metal layers of the PCB. Thenon-uniformly sized via catch pads may thus provide an obstruction tothe transmission of light through otherwise transmissive dielectricregions of the PCB around the via. The overlap or interposition allowsthe two sides of the PCB to be optically isolated from each other. Thus,components mounted on a first side of the PCB can be isolated from lightand other electromagnetic radiation incident on a second side of thePCB, and vice versa.

In a first embodiment, a Printed Circuit Board (PCB) is provided thatincludes a via extending through at least one layer of the PCB. The PCBalso includes a first catch pad connected to the via and located withina first metal layer of the PCB. The first catch pad has a first size.The PCB further includes a second catch pad connected to the via andlocated within a second metal layer of the PCB. The second catch pad hasa second size greater than the first size. Additionally, the secondcatch pad overlaps horizontally with a portion of a metallic feature inthe first metal layer to obstruct light incident on a first side of thePCB from transmission to a second side of the PCB through a region ofdielectric material near the via.

In a second embodiment, a method of manufacturing a Printed CircuitBoard (PCB) is provided that includes providing a PCB substrate. Themethod also includes creating a first metal layer on the PCB substrate.The first metal layer includes a first catch pad for a via. The firstcatch pad has a first size. The method additionally includes creating asecond metal layer on the PCB substrate. The second metal layer includesa second catch pad for the via. The second catch pad has a second sizegreater than the first size. The second catch pad overlaps horizontallywith a portion of a metallic feature in the first metal layer toobstruct light incident on a first side of the PCB from transmission toa second side of the PCB through a region of the PCB substrate near thevia. The method further includes creating the via. The via electricallyconnects the first catch pad to the second catch pad.

In a third embodiment, a system is provided that includes a PrintedCircuit Board (PCB) including a first side and a second side. The systemalso includes a light sensor connected to the second side of the PCB andconfigured to sense light incident on the light sensor from the secondside of the PCB. The system additionally includes a via extendingthrough at least one layer of the PCB. The system further includes afirst catch pad connected to the via and located within a first metallayer of the PCB. The first catch pad has a first size. The system yetfurther includes a second catch pad connected to the via and locatedwithin a second metal layer of the PCB. The second catch pad has asecond size greater than the first size. The second catch pad overlapshorizontally with a portion of a metallic feature in the first metallayer to obstruct light incident on the first side of the PCB fromtransmission to the second side of the PCB through a region oftransmissive PCB material near the via and striking the light sensor.

In a fourth embodiment, a device is provided formed by a process thatincludes providing a Printed Circuit Board (PCB) substrate. The processalso includes creating a first metal layer on the PCB substrate. Thefirst metal layer includes a first catch pad for a via. The first catchpad has a first size. The process additionally includes creating asecond metal layer on the PCB substrate. The second metal layer includesa second catch pad for the via. The second catch pad has a second sizegreater than the first size. The second catch pad overlaps horizontallywith a portion of a metallic feature in the first metal layer toobstruct light incident on a first side of the PCB from transmission toa second side of the PCB through a region of the PCB substrate near thevia. The process further includes creating the via. The via electricallyconnects the first catch pad to the second catch pad.

In a fifth embodiment, an integrated circuit (IC) device is providedthat includes a via extending through at least one layer of the ICdevice. The IC device also includes a first catch pad connected to thevia and located within a first metal layer of the IC device. The firstcatch pad has a first size. The IC device further includes a secondcatch pad connected to the via and located within a second metal layerof the IC device. The second catch pad has a second size greater thanthe first size. Additionally, the second catch pad overlaps horizontallywith a portion of a metallic feature in the first metal layer toobstruct light incident on a first side of the IC device fromtransmission to a second side of the IC device through a region oftransmissive material near the via.

In a sixth embodiment, a method of manufacturing an integrated circuit(IC) device is provided that includes providing an IC substrate. Themethod also includes creating a first metal layer on the IC substrate.The first metal layer includes a first catch pad for a via. The firstcatch pad has a first size. The method additionally includes creating asecond metal layer on the IC substrate. The second metal layer includesa second catch pad for the via. The second catch pad has a second sizegreater than the first size. The second catch pad overlaps horizontallywith a portion of a metallic feature in the first metal layer toobstruct light incident on a first side of the IC device fromtransmission to a second side of the IC device through a region of theIC substrate near the via. The method further includes creating the via.The via electrically connects the first catch pad to the second catchpad.

In a seventh embodiment, a system is provided that includes anintegrated circuit (IC) device having a first side and a second side.The system also includes a light sensor connected to the second side ofthe IC device and configured to sense light incident on the light sensorfrom the second side of the IC device. The system additionally includesa via extending through at least one layer of the IC device. The systemfurther includes a first catch pad connected to the via and locatedwithin a first metal layer of the IC device. The first catch pad has afirst size. The system yet further includes a second catch pad connectedto the via and located within a second metal layer of the IC device. Thesecond catch pad has a second size greater than the first size. Thesecond catch pad overlaps horizontally with a portion of a metallicfeature in the first metal layer to obstruct light incident on the firstside of the IC device from transmission to the second side of the ICdevice through a region of transmissive IC device substrate materialnear the via and striking the light sensor.

In an eighth embodiment, a device is provided formed by a process thatincludes providing an integrated circuit (IC) substrate. The processalso includes creating a first metal layer on the IC substrate. Thefirst metal layer includes a first catch pad for a via. The first catchpad has a first size. The process additionally includes creating asecond metal layer on the IC substrate. The second metal layer includesa second catch pad for the via. The second catch pad has a second sizegreater than the first size. The second catch pad overlaps horizontallywith a portion of a metallic feature in the first metal layer toobstruct light incident on a first side of the IC from transmission to asecond side of the IC through a region of the IC substrate near the via.The process further includes creating the via. The via electricallyconnects the first catch pad to the second catch pad.

These as well as other embodiments, aspects, advantages, andalternatives will become apparent to those of ordinary skill in the artby reading the following detailed description, with reference whereappropriate to the accompanying drawings. Further, it should beunderstood that this summary and other descriptions and figures providedherein are intended to illustrate embodiments by way of example onlyand, as such, that numerous variations are possible. For instance,structural elements and process steps can be rearranged, combined,distributed, eliminated, or otherwise changed, while remaining withinthe scope of the embodiments as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a block diagram of an example LIDAR device, accordingto an example embodiment.

FIG. 2 illustrates a simplified block diagram of a vehicle, according toan example embodiment.

FIG. 3 illustrates several views of a LIDAR device positioned on top ofa vehicle, according to an example embodiment.

FIG. 4 illustrates a lateral cross-sectional view of a Printed CircuitBoard with uniform via pads, according to an example embodiment.

FIG. 5A illustrates a lateral cross-sectional view of a Printed CircuitBoard with nonuniform via pads, according to an example embodiment.

FIG. 5B illustrates a lateral cross-sectional view of another PrintedCircuit Board with nonuniform via pads, according to an exampleembodiment.

FIG. 5C illustrates a lateral cross-sectional view of a further PrintedCircuit Board with nonuniform via pads, according to an exampleembodiment.

FIG. 6A illustrates a top view of a Printed Circuit Board with uniformvia pads, according to an example embodiment.

FIG. 6B illustrates a top view of a Printed Circuit Board withnonuniform via pads, according to an example embodiment.

FIG. 7 illustrates a light sensor housed within an enclosure, accordingto an example embodiment.

FIG. 8 illustrates example operations for manufacturing a printedcircuit board, according to an example embodiment.

DETAILED DESCRIPTION

Example methods, devices, and systems are described herein. It should beunderstood that the words “example” and “exemplary” are used herein tomean “serving as an example, instance, or illustration.” Any embodimentor feature described herein as being an “example” or “exemplary” is notnecessarily to be construed as preferred or advantageous over otherembodiments or features unless indicated as such. Other embodiments canbe utilized, and other changes can be made, without departing from thescope of the subject matter presented herein.

Thus, the example embodiments described herein are not meant to belimiting. It will be readily understood that the aspects of the presentdisclosure, as generally described herein, and illustrated in thefigures, can be arranged, substituted, combined, separated, and designedin a wide variety of different configurations.

Throughout this description, the articles “a” or “an” are used tointroduce elements of the example embodiments. Any reference to “a” or“an” refers to “at least one,” and any reference to “the” refers to “theat least one,” unless otherwise specified, or unless the context clearlydictates otherwise. The intent of using the conjunction “or” within adescribed list of at least two terms is to indicate any of the listedterms or any combination of the listed terms.

The use of ordinal numbers such as “first,” “second,” “third” and so onis to distinguish respective elements rather than to denote a particularorder of those elements. For purpose of this description, the terms“multiple” and “a plurality of” refer to “two or more” or “more thanone.”

Further, unless context suggests otherwise, the features illustrated ineach of the figures may be used in combination with one another. Thus,the figures should be generally viewed as component aspects of one ormore overall embodiments, with the understanding that not allillustrated features are necessary for each embodiment. In the figures,similar symbols typically identify similar components, unless contextdictates otherwise. Further, unless otherwise noted, figures are notdrawn to scale and are used for illustrative purposes only. Moreover,the figures are representational only and not all components are shown.For example, additional structural or restraining components might notbe shown.

Additionally, any enumeration of elements, blocks, or steps in thisspecification or the claims is for purposes of clarity. Thus, suchenumeration should not be interpreted to require or imply that theseelements, blocks, or steps adhere to a particular arrangement or arecarried out in a particular order.

I. Overview

Disclosed herein are example embodiments of non-uniform via (i.e.,vertical interconnect access) catch pads, as well as methods and systemsrelating thereto. The non-uniform catch pads can block light frompassing through a Printed Circuit Board (PCB) and causing unwantedtriggering of sensitive light sensors. The catch pads may be implementin Light Detection And Ranging (LIDAR) PCBs, for example, or otherapplications that use sensitive light sensors. A LIDAR system may emitlight using one or more transmitters (e.g., laser diodes) and receiveback light using one or more corresponding receivers (e.g., sensors) tomeasure distance (and in some cases speed) of objects in the line ofsight of the LIDAR. Receiver circuits may be based on very sensitiveelements (like PhotoMultiplier Tubes (PMT), Avalanche PhotoDiodes (APD),and Silicon PhotoMultipliers (SiPM)) that, working in conjunction withan amplifier circuit, may allow the detection of a single photon. Thishigh sensitivity to light may improve LIDAR resolution and range, butmay lead to challenges in designing a system in which the overall LIDARassembly and, in particular, the area around the sensitive light sensoris properly shielded against unintended or loose photons that couldcause unwanted effects (e.g., unwanted triggering of the circuit,increased current consumption, etc.). In one embodiment, a non-uniformvia pad-stack (in conjunction with filled vias) is adopted such thatlight can get reflected out of the PCB or absorbed internally by themetallization layers instead of passing through the PCB. Designing thevia pad-stack in a manner that blocks loose photons from passing throughthe PCB may also allow inexpensive solder masks (e.g., green) to be usedwith light sensitive PCBs.

Via catch pads are conductive metal pads, often in the shape of annularrings, around the via. In some instances, a via catch pad may provide anelectrical connection between the via and at least one metallic featurein a corresponding metal layer of the PCB. However, in other instances,the via catch pad might not be electrically connected to any metallicfeatures in the corresponding metal layer (e.g., a catch pad of astacked microvia). The non-uniformly sized via catch pads may extendinto transmissive regions of the PCB around the via to provide anobstruction to the transmission of light through the otherwisetransmissive regions around the via. In some instances, thenon-uniformly sized catch pads may also overlap with or interposebetween metallic features (e.g., traces, planes, pads) in adjacent metallayers of the PCB to further increase the likelihood of obstructing thetransmission of light through the otherwise transmissive regions of thePCB around the via. The non-uniformly sized catch pads allow the twosides of the PCB to be optically isolated from each other. Thus,components mounted on a first side of the PCB can be isolated from lightand other electromagnetic radiation incident on a second side of thePCB, and vice versa.

Conventionally, vias include catch pads of approximately (i.e.,encompassing variations in manufacturing tolerances and manufacturingprocess variations) the same size. A minimum clearance space or gap,comprised of a transmissive dielectric PCB substrate material, may beprovided between each catch pad and any nearby metallic features withinthe same metal layer. The clearance space may serve to physicallyseparate and electrically isolate the catch pad from the nearby metallicfeatures and reduce the likelihood of inadvertent physical electricalconnections and flashovers. However, since the size of the via catchpads is uniform along the height of the via, this may result in adielectric PCB substrate region, spanning the thickness of the PCB,through which light can be transmitted between the two sides of the PCB.Thus, light-sensitive components connected to the first side of the PCBmay be inadvertently triggered by light or other electromagneticradiation incident on the second side of the PCB and transmitted throughthe transmissive dielectric PCB substrate region around the via. Incontrast, vias with nonuniform catch pads increase the probability ofobstructing the transmission of light through the transmissivedielectric PCB substrate region around the via, thereby reducing anamount of light transmitted through the PCB, by including at least onecatch pad that extends through the dielectric region.

Nonuniform via catch pads may be used with PCBs having two or more metallayers. In one example, a PCB may include a via extending through atleast one layer of the PCB. That is, the PCB may include at least twometal layers separated by a dielectric substrate layer through which thevia extends. The via may include at least two catch pads, each connectedto the via and located within a corresponding one of the metal layers. Afirst catch pad, having a first size, may be connected to the via andmay be located within a first metal layer of the PCB. A second catch padmay be connected to the via and may be located within a second metallayer of the PCB. In some examples, the first catch pad and the secondcatch pad may electrically connect the via to the first metal layer andthe second metal layer, respectively. The second catch pad may have asecond size greater than the first size and may thus extend through aregion of the dielectric substrate material around the via. In someinstances, the second catch pad may, due to the second larger size,overlap horizontally with a portion of a metallic feature in the firstmetal layer.

As a result of the second size being greater than the first size, thesecond catch pad may extend through a region of the PCB substrate that,if the first and second catch pads were of the same size, would betransmissive to light. Thus, the larger second catch pad obstructs lightincident on a first side of the PCB from transmission to a second sideof the PCB through the region of the dielectric PCB substrate near thevia. Metallic features in the second metal layer may be routed toaccommodate the increased size of the second catch pad and to maintain adesired clearance (i.e., spacing or separation) between the second catchpad and the metallic features. Similarly, in some embodiments, metallicfeatures in the first metal layer may be routed to create, along theentire circumference of the second catch pad, continuous horizontaloverlap between the metallic features in the first metal layer and thesecond catch pad.

The PCB may include additional metal layers through which the viaextends as well as additional catch pads connected to the via andlocated within the additional metal layers. The relative size of thecatch pads in the different metal layers may be selected to increase ormaximize the complexity of the path (e.g., the path length, the numberof reflections, etc.) that light would have to follow in order to movefrom the first side of the PCB to the second side of the PCB, thusreducing or minimizing the probability and extent of transmission.

In one example, a via may include catch pads of two sizes, which may bealternated along the metal layers to increase the extent of overlap andinterposition of the catch pads with metallic features in adjacent metallayers (i.e., the metal layers above and below the metal layercontaining a particular catch pad). In another example, via anti-pads(i.e., clearance regions around the via in a metal layer not including avia catch pad) may be positioned between the largest of the via catchpads to similarly increase the extent of overlap and interposition. In afurther example, the arrangement of the catch pads may be selected toobstruct light incident at a particular angle on the top surface of thePCB.

The metallic features in other regions of the PCB may also be designedand routed to ensure that, at every point along the area of the PCB,there is, in at least one metal layer, at least one metallic featurethat obstructs light from being directly transmitted between the twosides of the PCB. The metallic features may be further designed androuted to ensure that the at least one metallic feature overlapshorizontally with at least one other metallic feature in another metallayer. Thus, the PCB may be designed such that there is no point alongthe area of the PCB at which light may be transmitted through the PCBdirectly (i.e., without reflecting off of metallic features within thePCB). Notably, some light may nevertheless be transmitted by followingan indirect zigzag path. However, the likelihood of such indirecttransmission decreases with increasing extent of overlap betweenmetallic features. Further, even if the light is not reflected back outthe first side, it is likely that the light will be internally absorbedby the metal layers before reaching the second side. Thus, thetechniques herein described effectively reduce the likelihood and amountof light transmission through the PCB. That is, the likelihood of asingle photon being transmitted through the PCB may be reduced,therefore reducing the proportion of the light incident on the PCB thatgets transmitted through the PCB.

In some embodiments, a light sensor may be connected to the second sideof the PCB. The light sensor may be configured to sense light incidenton the light sensor from the second side of the PCB. That is, lightincident on the first side of the PCB, transmitted through the PCB, andincident on the light sensor may constitute undesirable noise.Accordingly, by overlapping horizontally with the portion of themetallic feature in the first metal layer, the second catch pad mayoperate to reduce the level of electromagnetic noise that reaches thelight sensor.

In some instances, the light sensor may form part of a Light Detectionand Ranging (LIDAR) device that may be used as a sensor for mapping outan environment. The map of the environment may be used, for example, bya robotic device or a vehicle to perform operations within theenvironment. An enclosure may be disposed about the light sensor. Theenclosure may include an aperture configured to direct light from aportion of an environment onto the light sensor. The light directed ontothe light sensor may include light emitted by a light source of theLIDAR device that has been reflected off of a physical feature in theenvironment, thus allowing for the mapping of the environment based on,for example, time of flight of the light emitted by the light source.

A gasket surrounding the light sensor may be disposed between the secondside of the PCB and the enclosure to further shield the light sensorfrom other optical noise. Specifically, the gasket may be configured toblock light incident on an interface between the PCB and the enclosure.Accordingly, the PCB with nonuniform via catch pads, the enclosure, andthe gasket may collectively operate to reduce the amount of opticalnoise reaching the light sensor, thus increasing the signal to noiseratio.

The PCB with nonuniform via catch pads may be used in other applicationsthat require electromagnetic shielding. For example, the PCB may be usedto provide more effective electromagnetic shielding from radiationincident on the first side of the PCB of other electromagnetic sensorsor other components sensitive to electromagnetic radiation that areconnected to a second side of the PCB. The PCB with nonuniform catchpads may be used to provide shielding from, for example, electromagneticradiation having a wavelength that is smaller than a size of the gap(i.e., slit size) in the dielectric PCB substrate region and thereforepropagates through the gap via line-of-sight propagation (e.g.,ultraviolet, visible, infrared).

The PCB with nonuniform catch pads may be manufactured using standardPCB manufacturing processes, including photolithography, metal etching,metal plating, laminating, solder resist application, legend printing,Computer Numerical Control (CNC) Milling, and laser drilling, amongother possibilities. These processes may be performed manually,automatically, or by a combination of manual and automated steps.Similarly, the process of designing the PCB with nonuniform via catchpads may be performed by a combination of manual and automated steps.For example, PCB design software may be programmed to include a DesignRule Check (DRC) that verifies whether the PCB includes any points alongthe area thereof that are directly transmissible to light. The PCBdesign software may be further programmed to identify and indicatelocations where the design rule is not met and, in some embodiments,propose potential redesign of the metallic features to meet the designrule.

Nonuniform via catch pads may also be implemented on an integratedcircuit (IC) device, rather than a PCB, to obstruct the transmission oflight through transmissive regions of the integrated circuit devicesurrounding the via. Nonuniform catch pads, as well as any of the othertechniques herein described, may be used in combination with or insteadof IC packaging to obstruct the transmission of light through the IC.Non-transmissive IC packaging may obstruct the transmission of lightthrough packaged portions of the IC. However, some parts of the IC maybe left unpackaged or may be packaged by transmissive materials to, forexample, expose a portion of the IC to the environment (e.g., expose asensor on the IC to the environment). The nonuniform catch pads may beused to obstruct the transmission of light through the unpackaged orotherwise exposed portions of the IC.

The obstruction may reduce the likelihood of light incident on a firstside of the IC from being transmitted to a second side of the IC andpotentially striking a light-sensitive portion of the IC on the secondside thereof. Further, the obstruction may reduce the likelihood ofelectromagnetic radiation incident on either side of the IC fromreaching electronic components within the IC and potentially causinglatch-up. Other benefits due to the reduced transmission of lightthrough the IC may be possible.

II. Example LIDAR Devices

Referring now to the Figures, FIG. 1 is a simplified block diagram of aLIDAR device 100, according to an example embodiment. As shown, theLIDAR device 100 includes a power supply arrangement 102, electronics104, light source(s) 106, a transmitter 108, a receiver 110, a rotatingplatform 114, actuator(s) 116, a stationary platform 118, a rotary link120, and a housing 122. In other embodiments, the LIDAR device 100 mayinclude more, fewer, or different components. Additionally, thecomponents shown may be combined or divided in any number of ways.

Power supply arrangement 102 may be configured to supply power tovarious components of the LIDAR device 100. In particular, the powersupply arrangement 102 may include or otherwise take the form of atleast one power source disposed within the LIDAR device 100 andconnected to various components of the LIDAR device 100 in any feasiblemanner, so as to supply power to those components. Additionally oralternatively, the power supply arrangement 102 may include or otherwisetake the form of a power adapter or the like that is configured toreceive power from one or more external power sources (e.g., from apower source arranged in a vehicle to which the LIDAR device 100 iscoupled) and to supply that received power to various components of theLIDAR device 100 in any feasible manner. In either case, any type ofpower source may be used such as, for example, a battery.

Electronics 104 may include one or more electronic components and/orsystems each arranged to help facilitate certain respective operationsof the LIDAR device 100. In practice, these electronics 104 may bedisposed within the LIDAR device 100 in any feasible manner. Forinstance, at least some of the electronics 104 may be disposed within acentral cavity region of the rotary link 120. Nonetheless, theelectronics 104 may include various types of electronic componentsand/or systems.

For example, the electronics 104 may include various wirings used fortransfer of control signals from a controller to various components ofthe LIDAR device 100 and/or for transfer of data from various componentsof the LIDAR device 100 to the controller. Generally, the data that thecontroller receives may include sensor data based on detections of lightby the receiver 110, among other possibilities. Moreover, the controlsignals sent by the controller may operate various components of theLIDAR device 100, such as by controlling emission of light by thetransmitter 108, controlling detection of light by the receiver 110,and/or controlling the actuator(s) 116 to rotate the rotating platform114, among other possibilities.

In some arrangements, the electronics 104 may also include thecontroller at issue. This controller may have one or more processors,data storage, and program instructions stored on the data storage andexecutable by the one or more processor to facilitate variousoperations. Additionally or alternatively, the controller maycommunicate with an external controller or the like (e.g., a computingsystem arranged in a vehicle to which the LIDAR device 100 is coupled)so as to help facilitate transfer of control signals and/or data betweenthe external controller and the various components of the LIDAR device100.

In other arrangements, however, the electronics 104 may not include thecontroller at issue. Rather, at least some of the above-mentionedwirings may be used for connectivity to an external controller. Withthis arrangement, the wirings may help facilitate transfer of controlsignals and/or data between the external controller and the variouscomponents of the LIDAR device 100. Other arrangements are possible aswell.

Further, one or more light sources 106 can be configured to emit,respectively, a plurality of light beams and/or pulses havingwavelengths within a wavelength range. The wavelength range could, forexample, be in the ultraviolet, visible, and/or infrared portions of theelectromagnetic spectrum. In some examples, the wavelength range can bea narrow wavelength range, such as provided by lasers.

In some arrangements, the one or more light sources 106 may includelaser diodes, light emitting diodes (LED), vertical cavity surfaceemitting lasers (VCSEL), organic light emitting diodes (OLED), polymerlight emitting diodes (PLED), light emitting polymers (LEP), liquidcrystal displays (LCD), microelectromechanical systems (MEMS), and/orany other device configured to selectively transmit, reflect, and/oremit light to provide the plurality of emitted light beams and/orpulses.

In some embodiments, transmitter 108 may be configured to emit lightinto an environment. In particular, the transmitter 108 may include anoptical arrangement that is arranged to direct light from a light source106 toward the environment. This optical arrangement may include anyfeasible combination of mirror(s) used to guide propagation of the lightthroughout physical space and/or lens(es) used to adjust certaincharacteristics of the light, among other optical components. Forinstance, the optical arrangement may include a transmit lens arrangedto collimate the light, thereby resulting in light having rays that aresubstantially parallel to one another.

As noted, the LIDAR device 100 may include a receiver 110. The receivermay be configured to detect light having wavelengths in the samewavelength range as the one of the light emitted from the transmitter108. In this way, the LIDAR device 100 may distinguish reflected lightpulses originated at the LIDAR device 100 from other light in theenvironment.

Additionally, the receiver 110 may be configured to scan the environmentwith a field of view (FOV). For instance, the FOV of the receiver 110may allow for detection of light substantially along the same angularrange as the light emitted by transmitter 108. In an exampleimplementation, the receiver 110 may have an optical arrangement thatallows the receiver to provide the FOV a particular resolution.Generally, such optical arrangement may be arranged to provide anoptical path between at least one optical lens and a photodetectorarray.

In one implementation, the receiver 110 may include an optical lensarranged to focus light reflected from one or more objects in theenvironment of the LIDAR device 100 onto detectors of the receiver 110.

Furthermore, as noted, the receiver 110 may have a photodetector array,which may include one or more detectors configured to convert detectedlight (e.g., in the above-mentioned wavelength range) into an electricalsignal indicative of the detected light. In practice, such aphotodetector array could be arranged in one of various ways. Forexample, the detectors can be disposed on one or more substrates (e.g.,printed circuit boards (PCBs), flexible PCBs, etc.) and arranged todetect incoming light that is traveling along the optical path from theoptical lens. In general, a component disposed on a substrate may bedisposed above or beneath the substrate. Also, such a photodetectorarray could include any feasible number of detectors aligned in anyfeasible manner. For example, the photodetector array may include a13×16 array of detectors. It is noted that this photodetector array isdescribed for exemplary purposes only and is not meant to be limiting.

Generally, the detectors of the array may take various forms. Forexample, the detectors may take the form of photodiodes, avalanchephotodiodes, phototransistors, cameras, active pixel sensors (APS),charge coupled devices (CCD), cryogenic detectors, and/or any othersensor of light configured to receive focused light having wavelengthsin the wavelength range of the emitted light. Other examples arepossible as well.

Further, as noted, the LIDAR device 100 may include a rotating platform114 that is configured to rotate about an axis. In order to rotate inthis manner, one or more actuators 116 may actuate the rotating platform114. In practice, these actuators 116 may include motors, pneumaticactuators, hydraulic pistons, and/or piezoelectric actuators, amongother possibilities.

In accordance with the present disclosure, the transmitter 108 and thereceiver 110 may be arranged on the rotating platform such that each ofthese components moves relative to the environment based on rotation ofthe rotating platform 114. In particular, each of these components couldbe rotated relative to an axis so that the LIDAR device 100 may obtaininformation from various directions. In this manner, the LIDAR device100 may have a horizontal viewing direction that can be adjusted byactuating the rotating platform 114 to different directions.

With this arrangement, a controller could direct an actuator 116 torotate the rotating platform 114 in various ways so as to obtaininformation about the environment in various ways. In particular, therotating platform 114 could rotate at various extents and in eitherdirection. For example, the rotating platform 114 may carry out fullrevolutions such that the LIDAR device 100 provides a 360° horizontalFOV of the environment.

Moreover, the rotating platform 114 could rotate at various rates so asto cause LIDAR device 100 to scan the environment at various refreshrates. For example, the LIDAR device 100 may be configured to have arefresh rate of 15 Hz (e.g., fifteen complete rotations of the LIDARdevice 100 per second). In this example, assuming that the LIDAR device100 is coupled to a vehicle as further described below, the scanningthus involves scanning a 360° FOV around the vehicle fifteen times everysecond. Other examples are also possible.

Yet further, as noted, the LIDAR device 100 may include a stationaryplatform 118. In practice, the stationary platform may take on any shapeor form and may be configured for coupling to various structures, suchas to a top of a vehicle for example. Also, the coupling of thestationary platform may be carried out via any feasible connectorarrangement (e.g., bolts and/or screws). In this way, the LIDAR device100 could be coupled to a structure so as to be used for variouspurposes, such as those described herein.

In accordance with the present disclosure, the LIDAR device 100 may alsoinclude a rotary joint 120 that directly or indirectly couples thestationary platform 118 to the rotating platform 114. Specifically, therotary joint 120 may take on any shape, form and material that providesfor rotation of the rotating platform 114 about an axis relative to thestationary platform 118. For instance, the rotary joint 120 may take theform of a shaft or the like that rotates based on actuation from anactuator 116, thereby transferring mechanical forces from the actuator116 to the rotating platform 114. Moreover, as noted, the rotary jointmay have a central cavity in which electronics 104 and/or one or moreother components of the LIDAR device 100 may be disposed. Otherarrangements are possible as well.

Yet further, as noted, the LIDAR device 100 may include a housing 122.In practice, the housing 122 may take on any shape, form, and material.For example, the housing 122 can be a dome-shaped housing, among otherpossibilities. In another example, the housing 122 may be composed of amaterial that is at least partially non-transparent, which may allow forblocking of at least some light from entering the interior space of thehousing 122 and thus help mitigate thermal effects as further discussedbelow. It is noted that this housing is described for exemplary purposesonly and is not meant to be limiting.

In accordance with the present disclosure, the housing 122 may becoupled to the rotating platform 114 such that the housing 122 isconfigured to rotate about the above-mentioned axis based on rotation ofthe rotating platform 114. With this implementation, the transmitter108, the receiver 110, and possibly other components of the LIDAR device100 may each be disposed within the housing 122. In this manner, thetransmitter 108 and the receiver 110 may rotate along with this housing122 while being disposed within the housing 122.

Moreover, the housing 122 may have an aperture formed thereon, whichcould take on any feasible shape and size. In this regard, thetransmitter 108 could be arranged within the housing 122 so as to emitlight into the environment through the aperture. In this way, thetransmitter 108 may rotate along with the aperture due to correspondingrotation of the housing 122, thereby allowing for emission of light intovarious directions. Also, the receiver 110 could be arranged within thehousing 122 so as detect light that enters the housing 122 from theenvironment through the aperture. In this way, the receiver 110 mayrotate along with the aperture due to corresponding rotating of thehousing 122, thereby allowing for detection of the light incoming fromvarious directions along the horizontal FOV.

In practice, the housing 122 may be arranged as described above forvarious reasons. Specifically, due to various components of the LIDARdevice 100 being disposed within the housing 122 and due to the housing122 rotating along with those components, the housing 122 may helpprotect those components from various environmental hazards, such asrain and/or snow, among others. Also, if the housing 122 were to bestationary as the LIDAR device 100 rotates within the housing 122, thenthe housing 122 would likely be transparent so as to allow forpropagation of light through the housing 122 and thus for scanning ofthe environment by the LIDAR device 100.

In accordance with the present disclosure, however, the housing 122 mayhave the aperture that rotates along with the LIDAR device 100, whichmeans that the housing 122 does not necessarily need to be fullytransparent to allow for scanning of the environment. For example, thehousing 122 could be composed of at least a partially non-transparentmaterial, except for the aperture, which could be composed of atransparent material. As a result, the housing 122 may help mitigatethermal effects on the LIDAR device 100. For instance, the housing 122may block sun rays from entering the interior space of the housing 122,which may help avoid overheating of various components of the LIDARdevice 100 due to those sun rays. Other instances are possible as well.

Given the various components of the LIDAR device 100 as described above,these various components could be arranged in various ways. Inaccordance with the present disclosure, assuming that the LIDAR device100 is spatially oriented such that the stationary platform 118 isclosest to a ground surface, the LIDAR device 100 may be arranged suchthat the receiver 110 is positioned substantially above the stationaryplatform 118 and the transmitter 108 is positioned substantially abovethe receiver 110. However, it is noted that this arrangement isdescribed for exemplary purposes only and is not meant to be limiting.

III. Example Vehicle System

FIG. 2 is a simplified block diagram of a vehicle 200, according to anexample embodiment. The vehicle 200 may include a LIDAR device similarto the LIDAR device 100. As shown, the vehicle 200 includes a propulsionsystem 202, a sensor system 204, a control system 206 (could also bereferred to as a controller 206), peripherals 208, and a computer system210. In other embodiments, the vehicle 200 may include more, fewer, ordifferent systems, and each system may include more, fewer, or differentcomponents.

Additionally, the systems and components shown may be combined ordivided in any number of ways. For instance, the control system 206 andthe computer system 210 may be combined into a single system thatoperates the vehicle 200 in accordance with various operations.

The propulsion system 202 may be configured to provide powered motionfor the vehicle 200. As shown, the propulsion system 202 includes anengine/motor 218, an energy source 220, a transmission 222, andwheels/tires 224.

The engine/motor 218 may be or include any combination of an internalcombustion engine, an electric motor, a steam engine, and a Sterlingengine. Other motors and engines are possible as well. In someembodiments, the propulsion system 202 may include multiple types ofengines and/or motors. For instance, a gas-electric hybrid car mayinclude a gasoline engine and an electric motor. Other examples arepossible.

The energy source 220 may be a source of energy that powers theengine/motor 218 in full or in part. That is, the engine/motor 218 maybe configured to convert the energy source 220 into mechanical energy.Examples of energy sources 220 include gasoline, diesel, propane, othercompressed gas-based fuels, ethanol, solar panels, batteries, and othersources of electrical power. The energy source(s) 220 may additionallyor alternatively include any combination of fuel tanks, batteries,capacitors, and/or flywheels. In some embodiments, the energy source 220may provide energy for other systems of the vehicle 200 as well.

The transmission 222 may be configured to transmit mechanical power fromthe engine/motor 218 to the wheels/tires 224. To this end, thetransmission 222 may include a gearbox, clutch, differential, driveshafts, and/or other elements. In embodiments where the transmission 222includes drive shafts, the drive shafts may include one or more axlesthat are configured to be coupled to the wheels/tires 224.

The wheels/tires 224 of vehicle 200 may be configured in variousformats, including a unicycle, bicycle/motorcycle, tricycle, orcar/truck four-wheel format. Other wheel/tire formats are possible aswell, such as those including six or more wheels. In any case, thewheels/tires 224 may be configured to rotate differentially with respectto other wheels/tires 224. In some embodiments, the wheels/tires 224 mayinclude at least one wheel that is fixedly attached to the transmission222 and at least one tire coupled to a rim of the wheel that could makecontact with the driving surface. The wheels/tires 224 may include anycombination of metal and rubber, or combination of other materials. Thepropulsion system 202 may additionally or alternatively includecomponents other than those shown.

The sensor system 204 may include a number of sensors configured tosense information about an environment in which the vehicle 200 islocated, as well as one or more actuators 236 configured to modify aposition and/or orientation of the sensors. As shown, the sensors of thesensor system 204 include a Global Positioning System (GPS) 226, aninertial measurement unit (IMU) 228, a RADAR unit 230, a laserrangefinder and/or LIDAR unit 232, and a camera 234. The sensor system204 may include additional sensors as well, including, for example,sensors that monitor internal systems of the vehicle 200 (e.g., an 02monitor, a fuel gauge, an engine oil temperature, etc.). Other sensorsare possible as well.

The GPS 226 may be any sensor (e.g., location sensor) configured toestimate a geographic location of the vehicle 200. To this end, the GPS226 may include a transceiver configured to estimate a position of thevehicle 200 with respect to the Earth. The GPS 226 may take other formsas well.

The IMU 228 may be any combination of sensors configured to senseposition and orientation changes of the vehicle 200 based on inertialacceleration. In some embodiments, the combination of sensors mayinclude, for example, accelerometers and gyroscopes. Other combinationsof sensors are possible as well.

The RADAR unit 230 may be any sensor configured to sense objects in theenvironment in which the vehicle 200 is located using radio signals. Insome embodiments, in addition to sensing the objects, the RADAR unit 230may additionally be configured to sense the speed and/or heading of theobjects.

Similarly, the laser range finder or LIDAR unit 232 may be any sensorconfigured to sense objects in the environment in which the vehicle 200is located using lasers. For example, LIDAR unit 232 may include one ormore LIDAR devices, at least some of which may take the form the LIDARdevice 100 disclosed herein.

The camera 234 may be any camera (e.g., a still camera, a video camera,etc.) configured to capture images of the environment in which thevehicle 200 is located. To this end, the camera may take any of theforms described above. The sensor system 204 may additionally oralternatively include components other than those shown.

The control system 206 may be configured to control operation of thevehicle 200 and its components. To this end, the control system 206 mayinclude a steering unit 238, a throttle 240, a brake unit 242, a sensorfusion algorithm 244, a computer vision system 246, a navigation orpathing system 248, and an obstacle avoidance system 250.

The steering unit 238 may be any combination of mechanisms configured toadjust the heading of vehicle 200. The throttle 240 may be anycombination of mechanisms configured to control the operating speed ofthe engine/motor 218 and, in turn, the speed of the vehicle 200. Thebrake unit 242 may be any combination of mechanisms configured todecelerate the vehicle 200. For example, the brake unit 242 may usefriction to slow the wheels/tires 224. As another example, the brakeunit 242 may convert the kinetic energy of the wheels/tires 224 toelectric current. The brake unit 242 may take other forms as well.

The sensor fusion algorithm 244 may be an algorithm (or a computerprogram product storing an algorithm) configured to accept data from thesensor system 204 as an input. The data may include, for example, datarepresenting information sensed at the sensors of the sensor system 204.The sensor fusion algorithm 244 may include, for example, a Kalmanfilter, a Bayesian network, an algorithm for some of the functions ofthe methods herein, or any other algorithm. The sensor fusion algorithm244 may further be configured to provide various assessments based onthe data from the sensor system 204, including, for example, evaluationsof individual objects and/or features in the environment in which thevehicle 200 is located, evaluations of particular situations, and/orevaluations of possible impacts based on particular situations. Otherassessments are possible as well.

The computer vision system 246 may be any system configured to processand analyze images captured by the camera 234 in order to identifyobjects and/or features in the environment in which the vehicle 200 islocated, including, for example, traffic signals and obstacles. To thisend, the computer vision system 246 may use an object recognitionalgorithm, a Structure from Motion (SFM) algorithm, video tracking, orother computer vision techniques. In some embodiments, the computervision system 246 may additionally be configured to map the environment,track objects, estimate the speed of objects, etc.

The navigation and pathing system 248 may be any system configured todetermine a driving path for the vehicle 200. The navigation and pathingsystem 248 may additionally be configured to update the driving pathdynamically while the vehicle 200 is in operation. In some embodiments,the navigation and pathing system 248 may be configured to incorporatedata from the sensor fusion algorithm 244, the GPS 226, the LIDAR unit232, and one or more predetermined maps so as to determine the drivingpath for vehicle 200.

The obstacle avoidance system 250 may be any system configured toidentify, evaluate, and avoid or otherwise negotiate obstacles in theenvironment in which the vehicle 200 is located. The control system 206may additionally or alternatively include components other than thoseshown.

Peripherals 208 may be configured to allow the vehicle 200 to interactwith external sensors, other vehicles, external computing devices,and/or a user. To this end, the peripherals 208 may include, forexample, a wireless communication system 252, a touchscreen 254, amicrophone 256, and/or a speaker 258.

The wireless communication system 252 may be any system configured towirelessly couple to one or more other vehicles, sensors, or otherentities, either directly or via a communication network. To this end,the wireless communication system 252 may include an antenna and achipset for communicating with the other vehicles, sensors, servers, orother entities either directly or via a communication network. Thechipset or wireless communication system 252 in general may be arrangedto communicate according to one or more types of wireless communication(e.g., protocols) such as Bluetooth, communication protocols describedin IEEE 802.11 (including any IEEE 802.11 revisions), cellulartechnology (such as GSM, CDMA, UMTS, EV-DO, WiMAX, or LTE), Zigbee,dedicated short range communications (DSRC), and radio frequencyidentification (RFID) communications, among other possibilities. Thewireless communication system 252 may take other forms as well.

The touchscreen 254 may be used by a user to input commands to thevehicle 200. To this end, the touchscreen 254 may be configured to senseat least one of a position and a movement of a user's finger viacapacitive sensing, resistance sensing, or a surface acoustic waveprocess, among other possibilities. The touchscreen 254 may be capableof sensing finger movement in a direction parallel or planar to thetouchscreen surface, in a direction normal to the touchscreen surface,or both, and may also be capable of sensing a level of pressure appliedto the touchscreen surface. The touchscreen 254 may be formed of one ormore translucent or transparent insulating layers and one or moretranslucent or transparent conducting layers. The touchscreen 254 maytake other forms as well.

The microphone 256 may be configured to receive audio (e.g., a voicecommand or other audio input) from a user of the vehicle 200. Similarly,the speakers 258 may be configured to output audio to the user of thevehicle 200. The peripherals 208 may additionally or alternativelyinclude components other than those shown.

The computer system 210 may be configured to transmit data to, receivedata from, interact with, and/or control one or more of the propulsionsystem 202, the sensor system 204, the control system 206, and theperipherals 208. To this end, the computer system 210 may becommunicatively linked to one or more of the propulsion system 202, thesensor system 204, the control system 206, and the peripherals 208 by asystem bus, network, and/or other connection mechanism (not shown).

In one example, the computer system 210 may be configured to controloperation of the transmission 222 to improve fuel efficiency. As anotherexample, the computer system 210 may be configured to cause the camera234 to capture images of the environment. As yet another example, thecomputer system 210 may be configured to store and execute instructionscorresponding to the sensor fusion algorithm 244. As still anotherexample, the computer system 210 may be configured to store and executeinstructions for determining a 3D representation of the environmentaround the vehicle 200 using the LIDAR unit 232. Other examples arepossible as well. Thus, the computer system 210 could function as thecontroller for the LIDAR unit 232.

As shown, the computer system 210 includes the processor 212 and datastorage 214. The processor 212 may comprise one or more general-purposeprocessors and/or one or more special-purpose processors. To the extentthe processor 212 includes more than one processor, such processorscould work separately or in combination. Data storage 214, in turn, maycomprise one or more volatile and/or one or more non-volatile storagecomponents, such as optical, magnetic, and/or organic storage, and datastorage 214 may be integrated in whole or in part with the processor212.

In some embodiments, data storage 214 may contain instructions 216(e.g., program logic) executable by the processor 212 to execute variousvehicle functions. Data storage 214 may contain additional instructionsas well, including instructions to transmit data to, receive data from,interact with, and/or control one or more of the propulsion system 202,the sensor system 204, the control system 206, and/or the peripherals208. The computer system 210 may additionally or alternatively includecomponents other than those shown.

As shown, the vehicle 200 further includes a power supply 260, which maybe configured to provide power to some or all of the components of thevehicle 200. To this end, the power supply 260 may include, for example,a rechargeable lithium-ion or lead-acid battery. In some embodiments,one or more banks of batteries could be configured to provide electricalpower. Other power supply materials and configurations are possible aswell. In some embodiments, the power supply 260 and energy source 220may be implemented together as one component, as in some all-electriccars.

In some embodiments, the vehicle 200 may include one or more elements inaddition to or instead of those shown. For example, the vehicle 200 mayinclude one or more additional interfaces and/or power supplies. Otheradditional components are possible as well. In such embodiments, datastorage 214 may further include instructions executable by the processor212 to control and/or communicate with the additional components.

Still further, while each of the components and systems are shown to beintegrated in the vehicle 200, in some embodiments, one or morecomponents or systems may be removably mounted on or otherwise connected(mechanically or electrically) to the vehicle 200 using wired orwireless connections. The vehicle 200 may take other forms as well.

FIG. 3 shows a Right Side View, Front View, Back View, and Top View ofthe vehicle 300. As shown, the vehicle 300 includes the LIDAR device 100being positioned on a top side of the vehicle 300 opposite a bottom sideon which wheels 302 of the vehicle 300 are located. Although the LIDARdevice 100 is shown and described as being positioned on the top side ofthe vehicle 300, the LIDAR device 100 could be positioned on anyfeasible portion or part of the vehicle without departing from the scopeof the present disclosure.

Moreover, the LIDAR device 100 may be configured to scan an environmentaround the vehicle 300 (e.g., at a refresh rate of 15 Hz) by rotatingabout the vertical axis while emitting one or more light pulses anddetecting reflected light pulses off objects in the environment of thevehicle 300, for example. Further, in some implementations, multipleLIDAR devices could be positioned on different portions of the vehicle(e.g., one LIDAR device on each corner of the vehicle) so that eachLIDAR device is able to scan a different portion of the environment.

IV. Example PCB with Optical Isolation

FIG. 4 illustrates a lateral cross-section of an example Printed CircuitBoard (PCB) 400. PCB 400 includes metal layers 401, 404, 406, and 408,top solder mask 418, and bottom solder mask 424. PCB 400 also includesvia 410 (i.e., a vertical interconnect access) with corresponding catchpads 403, 405, 407, and 409. Light sensor 402 may be connected to PCB400 by way of solder pads 420 a and 420 b. PCB 400 may be mounted in ornear enclosure 414 which defines an aperture 422 for light to be sensedby light sensor 402. PCB 400 may include regions 416 a and 416 b oftransmissive PCB substrate material that may permit light 412 incidenton the top of PCB 400 to be directly transmitted to the bottom of PCB400, reflect off of enclosure 414 or another reflective surface, andstrike light sensor 402.

Metal layers 401, 404, 406, and 408 of PCB 400 may be separated from oneanother by regions of the PCB substrate material (e.g., FR-4glass-reinforced epoxy laminate), as indicated by the cross-hatchedpattern. The metal layers may include various metallic features 430A,430B, 450A, 450B, 470A, 470B, 490A, and 490B (i.e., metallic features430A-490B) such as, for example, traces (e.g., signal traces), contactpads (e.g., solder pads, via catch pads), and planes (e.g., groundplanes, power planes). The various metallic features 430A-490B may makeup the electrical connections that result in PCB 400 operating accordingto a desired design (e.g., powering light sensor 402 and providing anelectrical communication path between light sensor 402 and a processor).Notably, metallic features in a particular layer may be electricallyconnected or disconnected from one another and from other metallicfeatures in other layers, as needed to establish the desiredinterconnections between components on the PCB.

PCB 400 also includes via 410 electrically connecting at least two ofthe metal layers 401, 404, 406, and 408. Specifically, via 410 iselectrically connected to catch pads 403, 405, 407, and 409. Catch pad403 may, in some instances, electrically connect via 410 to at least onemetallic feature in metal layer 401. Similarly, catch pad 405 mayelectrically connect via 410 to at least one metallic feature in metallayer 404, catch pad 407 may electrically connect via 410 to at leastone metallic feature in metal layer 406, and catch pad 409 mayelectrically connect via 410 to at least one metallic feature in metallayer 408.

Although via 410 is shown as a through-hole via, via 410 may, in otherembodiments, be a blind via, extending through only a portion of thelayers of PCB 400 with one end of the via exposed to either the topsurface or the bottom surface of PCB 400, or a buried via, extendingthrough only a portion of the layers of PCB 400 with neither end of thevia exposed to the top surface or the bottom surface of PCB 400. Via 410may, in some embodiments, be a microvia (e.g., a stacked microvia) usedin a high density interconnect (HDI) PCB. Further, in some examples, via410 may for part of a staggered via structure or a staggered microviastructure. In some implementations, via 410 may be filled with aconductive or nonconductive material.

In general, catch pads 403, 405, 407, and 409 may be regions of metalelectrically connected to via 410 and may, in some embodiments,electrically connect via 410 to metallic features 430A-490B inrespective metal layers 401, 404, 406, and 408. In some embodiments, thecatch pads may be annular rings surrounding via 410. Specifically, anannular ring may have an inner circumference and an outer circumference,as well as corresponding inner and outer diameters. The innercircumference of the annular ring may be in contact with via 410, andthe area between the inner and outer circumference of the annular ringmay be filled with metal or another conductive and non-transmissivematerial. In other embodiments, the catch pad may take on differentshapes such as, for example, a square or a rectangle. That is, the outerboundary of the catch pad may be square or rectangular while a circularhole defines the inner circumference in contact with via 410. The catchpad may be continuous, completely surrounding via 410, or discontinuous,partially surrounding via 410.

FIG. 4 further illustrates light sensor 402 connected to the bottom ofPCB 400. In particular, light sensor 402 may be soldered or otherwisebonded to pads 420 a and 420 b, as well as other pads (not shown), toprovide an electrical connection to PCB 400. PCB 400 and light sensor402 may be positioned near enclosure 414 defining an aperture 422through which light may be directed onto the light sensor. In oneexample, light sensor 402 may be part of a LIDAR device (e.g., LIDARdevice 100). Light emitted by a light source of the LIDAR device may,after reflecting from a feature within an environment, be transmittedthrough aperture 422 to be detected by light sensor 402. Lighttransmitted through aperture 422 and incident on light sensor 402 may bereferred to as “signal” light because it may provide information aboutfeatures within the environment (e.g., based on time of flight of thelight emitted by the light source of the LIDAR).

However, light sensor 402 may also detect noise light and otherelectromagnetic radiation, thus producing inaccurate measurements. Forexample, light 412 incident on the top surface of PCB 400 may betransmitted from the top side of PCB 400 to the bottom side of PCB 400by way of regions 416 a and 416 b of the PCB substrate material (i.e.,dielectric material). Light 412 may subsequently reflect off ofenclosure 414 or another reflective surface and strike light sensor 402,thus producing a false reading. The magnitude of the problem may becompounded because light sensor 402 may be very sensitive, allowing forthe detection of even a single photon. Light sensor 402 may be or mayinclude, for example, PhotoMultiplier Tubes (PMT), Avalanche PhotoDiodes(APD), Silicon PhotoMultipliers (SiPM), PIN Diodes, complementary metaloxide semiconductor (CMOS) sensors, and charge coupled device (CCD)sensors. Thus, even very small amounts of noise light (e.g., severalphotons) may significantly interfere with the signal light receivedthrough aperture 422.

FIG. 5A illustrates a lateral cross-section of another example PCB 500.Similarly to PCB 400 shown in FIG. 4 , PCB 500 includes metal layers502, 504, 506, and 508, top solder mask 518, bottom solder mask 522, via510, light sensor 402 connected to PCB 500 by way of solder pads 520 aand 520 b. The metal layers may include various metallic features 530A,530B, 550A, 550B, 570A, 570B, 590A, and 590B (i.e., metallic features530A-590B). However, whereas the catch pads 403, 405, 407, and 409 ofPCB 400 all have approximately the same size, catch pads catch pads 503,505, 507, and 509 of PCB 500 are nonuniform.

In particular, the size of catch pads 505 and 509 is greater than thesize of catch pads 503 and 507. Thus, catch pads 505 and 509 extendthrough regions 516 a and 516 b of the PCB substrate and horizontallyoverlap with other metallic features 530A, 530B, 570A, and 570B inadjacent metal layers 502 and 506. Accordingly, whereas regions 416 aand 416 b of PCB 400 provide a direct transmission path for light 412,the nonuniform sizing of catch pads 503, 505, 507, and 509 of PCB 500provides an obstruction to the direct transmission of light 412 throughregions 516 a and 516 b, thereby reducing the probability that noiselight incident on the top side of PCB 500 will be transmitted to thebottom side of PCB 500 and reach light sensor 402. As a result of thereduced probability of transmission of the light, the amount orproportion of the noise light incident on the top side of PCB 500 thatends up transmitted to the bottom side of PCB 500 is also reduced.

In one example, catch pads 503 and 507 may be annular rings having anouter diameter of 15 mils (i.e., thousandths of an inch) and catch pads505 and 509 may be annular rings having an outer diameter of 35 mils.Thus, the diameter of the larger catch pads may be more than twice theouter diameter of the smaller catch pads. The inner diameter of catchpads 503, 505, 507, and 509, as well as the outer diameter of via 510,may be 5 mils.

Further, in addition to spanning regions 516 a and 516 b, catch pad 505may horizontally overlap with a plurality of metallic features in metallayers 502 and 506. Similarly, in addition to spanning regions 516 a and516 b, catch pad 509 may horizontally overlap with a plurality ofmetallic features in metal layer 506. Metallic features 550A, 550B,590A, and 590B in layers 504 and 508 may be rearranged to accommodatethe increased size of catch pads 505 and 509, respectively. In someembodiments, metallic features 530A, 530B, 570A, and 570B in layers 502and 506 may also be rearranged to ensure that, at every point along thehorizontal extent of PCB substrate regions 516 a and 516 b, there isoverlap between at least one of catch pads 505 or 509 and at least onemetallic feature in layers 502 or 506.

When PCB 500 is viewed from the top or the bottom, this overlap mayresult in the PCB substrate regions 516 a and 516 b being spanned at allpoints by at least one metal layer. That is, the non-uniformity of catchpads 503, 505, 507, and 509 may have the effect of masking or shieldingall dielectric substrate regions (e.g., 416 a and 416 b) by way of whichlight could directly pass through PCB 500.

Although some light may still make its way through PCB 500 by followingan indirect zigzag path between the overlapping metallic features, thenonuniform sizing of catch pads 503, 505, 507, and 509 reduces theprobability of this happening by creating a more tortuous path (e.g.,longer, including more reflections, etc.) that the light will have totake to be transmitted from the top side of PCB 500 to the bottom sideof PCB 500. Instead, light 412 is more likely to be reflected back outof PCB 500 or be internally absorbed by the metal layers of PCB 500. Thedifference in size between catch pads 503, 505, 507, and 509 may beadjusted to further reduce the probability of light 412 beingtransmitted through PCB 500. Similarly, the extent to which thenonuniform catch pads overlap horizontally with metallic features inadjacent layers may be increased to further reduce the probability oflight transmission. The reduced probability of transmission of light 412through PCB 500 thus results in a reduction in the amount or proportionof light incident on the top of PCB 500 that ends up transmitted throughregions 516 a and 516 b to the bottom of PCB 500.

The extent of optical isolation between the first and second sides ofPCB may be further improved by filling (i.e., depositing material intothe cavity of) or tenting (i.e., depositing material over the top of)via 510. Specifically, via 510 may be filled or tented with metal oranother optically non-transmissive material to prevent transmission oflight through the barrel (e.g., the center cavity or bore) of the via.

Further, in some embodiments, the extent of optical isolation may alsobe improved by using a dark (e.g., black) solder mask instead of a light(e.g., green) solder mask. The dark solder mask may absorb radiation inthe relevant portion of the electromagnetic spectrum, thus obstructingtransmission of light through the PCB. Notably, the minimum allowablefeature size of a dark solder mask may be larger than the minimumallowable feature size of a light solder mask. Thus, a dark solder maskmay be appropriate in some application or some regions of a PCB thatmeet the minimum size (e.g., pitch) requirement.

Notably, although the overlap of catch pads 505 and 509 with metallicfeatures in adjacent metal layers 502 and 506 is described as“horizontal,” it is to be understood that the term “horizontal” isintended to encompass changes in the direction of overlap resulting fromrotation of PCB 500. Thus, the horizontal overlap may be consideredhorizontal with respect to a horizontal plane of PCB 500 as illustratedin FIG. 5A. Accordingly, if PCB 500 is rotated by 90 degrees from theorientation shown in FIG. 5A, the overlap of catch pads 505 and 509 withmetal layers 502 and 508 will remain horizontal with respect to thehorizontal plane of PCB 500.

Additionally, although FIG. 5A illustrates a PCB with four metal layers,the nonuniform via catch pads may also be used with PCBs having more orfewer metal layers. In particular, FIG. 5B illustrates a lateralcross-section of PCB 524 which includes only two metal layers 502 and504 (i.e., PCB 500 with metal layers 506 and 508 removed). Thus, via 510includes only two catch pads 503 and 505. The size of catch pad 505 isgreater than the size of catch pad 503. Catch pad 505 overlaps withmetallic features in metal layer 502 to provide an obstruction to thetransmission of light 412 through regions 516 a and 516 b of PCB 524. Inparticular, catch pad 505 may overlap with a plurality of metallicfeatures in layer 502 such that, when viewed from the top, all pointsalong the area of PCB 524 are spanned by at least one metallic featureto provide an obstruction to the transmission of light through PCB 524.

In some embodiments, catch pad 505 might extend through the dielectricregions 516 a and 516 b without overlapping with metallic features 530Aand 530B in metal layer 502. Nevertheless, by spanning the dielectricregions 516 a and 516 b, catch pad 505 might help ensure that all pointsalong the area of PCB 524 are spanned by at least one metallic featureand thus provide an obstruction to the transmission of light through PCB524.

In some embodiments, a PCB may have more than four metal layers. Such aPCB may include, for example three instances of layers 502 and 504stacked on top of one another for a total of six layers. The six-layeredPCB may thus include three metal layers each including a correspondingvia catch pad having a first size (e.g., the size of catch pad 503). Thesix-layered PCB may also include three metal layers each including acorresponding via catch pad having a second size larger than the firstsize (e.g., the size of catch pad 505). In other embodiments, the PCBmay include an arbitrary number of layers as needed to define theelectrical connectivity of the PCB. Further, the relative sizes of thevia catch pads in the different layers may be varied as needed toaccommodate all requisite metallic features of the PCB, provided thatdielectric regions 516 a and 516 b are obstructed by at least one catchpad.

In some embodiments, the nonuniform via catch pads may also include viaanti-pads. FIG. 5C illustrates a lateral cross-section of PCB 526 whichincludes a via anti-pad 511 in metal layer 506. An anti-pad is a spacearound the via within a metal layer providing clearance between the viaand other metallic features within the metal layer. The anti-padisolates the via from metallic features within a corresponding metallayer (i.e., metallic features that are part of a different electricalnet and are not intended to be in electrical contact with the via) andthus reduces the likelihood of inadvertent electrical connections andflashovers (e.g., electrical connections via an air gap). Anti-pad 511,indicated by the dashed line, is the space about via 510 that provides aclearance between via 510 and metallic features 570A and 570B withinmetal layer 506. Due to the additional space provided by anti-pad 511 inPCB 526 relative to the catch pad 507 in PCB 500, the metallic features570A and 570B in metal layer 506 may be routed closer to via 510, thusincreasing the extent of overlap of catch pads 505 and 509 with metallicfeatures 570A and 570B in metal layer 506.

The layout of the metallic features within a layer of a PCB may bedetermined to improve or maximize the optical shielding provided by themetallic features of the PCB. For example, as illustrated in FIG. 5C, aPCB layout may be determined such that via anti-pads are positionedwithin a metal layer between two large via catch pads (e.g., catch pads505 and 509). In another example, the metallic features within layers ofthe PCB may be routed in a manner ensuring that all points along thearea of the PCB, when viewed from the top, contain a metallic feature inat least one layer of the PCB, thus obstructing the direct transmissionof light across the entire area of the PCB. Further, the metallicfeatures may be routed in a manner ensuring that there is at least aminimum extent of overlap between a metallic feature in a first metallayer and another metallic feature in another metal layer of the PCB,thus ensuring at least a minimum number of reflections that a photonwould have to undergo to be transmitted between the two sides of thePCB.

Such design parameters may be implemented as a Design Rule Check (DRC)in a PCB design software. The DRC may identify and indicate regions orfeatures of the PCB that violate the design parameter (e.g., no directlight transmission paths), thus allowing a designer to reroute anyfeatures that violate the rule in order to correct the violation. Insome embodiments, the PCB design software may be configured toautomatically route or reroute metallic features to satisfy the designrules herein described.

FIGS. 6A and 6B illustrate a top view of a region of a three-layered PCBwith uniform catch pads and nonuniform catch pads, respectively. Inparticular, FIG. 6A illustrates the transmissive region that may resultwhen uniform via catch pads are used. In layer 1, the PCB includessolder pad 600 and a metal trace 602. A via is positioned below solderpad 600 and spans layers 1-3. The size of the via catch pads in layers1-3 is indicated by dashed line 620. In layer 2, the PCB includes metalplane 604 and metal trace 606 which connects to a corresponding viacatch pad in layer 2. Metallic features of layer 3 are visible throughthe clearance spacing between metal plane 604 and metal trace 606.

When all via catch pads are uniform, as shown in FIG. 6A, the spacingbetween the via catch pads and adjacent metallic features withincorresponding metal layers results in a transmissive region 616 of thePCB substrate (i.e., a region that does not contain any metallicfeatures in layers 1-3, as indicated by the white space about pad 600).Thus, light incident on the top of the PCB in region 616 may betransmitted through region 616 to the bottom of the PCB, potentiallystriking any light-sensitive elements positioned thereabout.

In contrast, when the via catch pad in layer 3 of the PCB is increasedin size, as illustrated in FIG. 6B by dashed line 622, the via catch padextends through the transmissive region 616 and underneath metal plane604 and metal trace 606 in layer 2. The catch pad in layer 3 thuscreates an obstruction 618 that blocks direct transmission of lightthrough the previously transmissive region 616. Since the catch pad inlayer 2, as shown in FIG. 6B, remains the same size as in FIG. 6A, metalplane 604 and trace 606 retain their original positioning relative tothe catch pad and thus overlap with the now-larger catch pad in layer 3.Accordingly, the nonuniform via catch pads operate to obstruct anydirect transmission paths around the via by extending at least one ofthe metal catch pads into the direct transmission paths.

The nonuniform catch pads, as well as the other techniques hereindisclosed, may also be used in an IC device. For example, FIG. 5A mayrepresent a cross-section of an IC device that includes thereinadditional active electronic components (not shown, e.g., transistors)configured to implement a desired functionality of the IC (e.g.,processing a signal from a sensor). In some implementations, lightsensor 402 may form part of the IC and may be exposed to the environmentsuch that light may reach sensor 402. As previously described, thenonuniform catch pads 503, 505, 507, and 509 may obstruct transmissionof light through otherwise transmissive regions 516 a and 516 b of theIC, thus shielding light sensor 402 from being struck by light incidenton the top side of the IC. The various structures herein described(e.g., vias, traces, catch pads, metal planes, active components) may becreated on a silicon substrate to form the IC using corresponding ICmanufacturing techniques (e.g., photolithography, doping, metallization,etching, chemical vapor deposition, ion implantation, passivation,encapsulation, etc.) and materials (e.g., silicon, boron, aluminum,phosphorus, arsenic, etc.).

V. Example LIDAR Device with PCB Having Optical Isolation

FIG. 7 illustrates a lateral cross-section of PCB 500 assembled withenclosure 700 surrounding light sensor 402. The assembly illustrated inFIG. 7 may form part of a LIDAR device and may be positioned within ahousing thereof. The LIDAR device, or a plurality thereof, may beconnected to various parts or portions of a vehicle to allow the vehicleto navigate based on a signal from the LIDAR. Light sensor 402 of theLIDAR device may include very sensitive elements such as PhotoMultiplierTubes (PMT), Avalanche PhotoDiodes (APD), Silicon PhotoMultipliers(SiPM), or PIN diodes that, working in conjunction with an amplifiercircuit, allow the detection of even just a single photon. Thus, it maybe advantageous to shield light sensor 402 from stray photons that couldcause unwanted triggering of light sensor 402.

Accordingly, enclosure 700 includes an aperture 722 through which lightfrom an environment may be selectively directed at light sensor 402. Theassembly also includes a gasket 702 positioned between enclosure 700 andthe bottom of PCB 500 to optically isolate the light sensor 402. Inparticular, gasket 702 obstructs light incident on the interface betweenenclosure 700 and PCB 500 from reaching light sensor 402. Further, PCBincludes nonuniform catch pads, as discussed with respect to FIG. 5A,that obstruct unwanted light incident on the top of PCB 500 fromtransmission through regions 516 a and 516 b to the bottom of PCB 500and triggering of light sensor 402.

PCB 500 and enclosure 700 may be rotated or otherwise repositioned toselectively direct light from an environment onto light sensor 402. Forexample, PCB 500 and enclosure 700 may be rotated along with the LIDARdevice, which includes a light source, to map out an environment of theLIDAR device. In particular, light sensor 402 may be used to map out theenvironment based on time of flight of light emitted by the light sourceof the LIDAR device. Aperture 722 may be used to selectively limit thelight reaching light sensor 402 to light containing the optical signalemitted by the light source and reflected back at the light sensor 402from a feature within the environment. The nonuniform catch pads 503,505, 507, and 509, enclosure 700, and gasket 702 may, in combination,reduce the amount of noise light (i.e., light that has not been emittedby the light source of the LIDAR device) reaching light sensor 402, thusimproving the accuracy of the LIDAR device in mapping out anenvironment.

VI. Example Method of Manufacturing a PCB with Optical Isolation

FIG. 8 illustrates an example flow chart 800 of operations formanufacturing a PCB that includes nonuniform catch pads. The operationsof flow chart 800 may be performed manually, automatically (e.g., by arobotic device), or using a combination of manual and automatedprocesses. The operations of flow chart 800 may be used to manufacture,for example, PCB 500, PCB 524, or PCB 526, illustrated in FIGS. 5A, 5B,and 5C, respectively.

In block 802, a Printed Circuit Board (PCB) substrate may be provided.The material of the PCB substrate may be chosen to provide the desireddielectric constant, tensile strength, shear strength, glass transitiontemperature, and expansion coefficient, among other properties. The PCBsubstrate may include, for example, polytetrafluoroethylene, FR-2(phenolic cotton paper), FR-3 (cotton paper and epoxy), FR-4 (wovenglass and epoxy), FR-5 (woven glass and epoxy), FR-6 (matte glass andpolyester), G-10 (woven glass and epoxy), CEM-1 (cotton paper andepoxy), CEM-2 (cotton paper and epoxy), CEM-3 (non-woven glass andepoxy), CEM-4 (woven glass and epoxy), CEM-5 (woven glass andpolyester), or ceramics (e.g., Aluminum Oxide (Al2O3) or AluminumNitride (AlN)), among other possibilities. Further, in some example, thePCB substrate may be a flexible PCB substrate (e.g., a polyimidesubstrate).

In block 804, a first metal layer may be created on the PCB substrate.The first metal layer may include a first catch pad for a via. The firstcatch pad may have a first size. The first metal layer may also includea plurality of other metallic features, including pads, traces, andplanes necessary to implement the desired electrical connectivity of thePCB.

Creating the first metal layer and the features thereof may includestarting with a metal-clad PCB substrate. Alternatively, anadhesive-backed sheet or film of metal may be bonded to a PCB substrate.A photoresist may be applied to the metal layer. The photoresist maythen be exposed through a mask and subsequently developed (i.e., exposedto UV light to polymerize the photoresist) to protect metal regionsdefining the desired features. The unprotected metal regions may beetched and the protective photoresist may be removed to reveal themetallic features.

In block 806, a second metal layer may be created on the PCB substrate.The second metal layer may include a second catch pad for the via. Thesecond catch pad may have a second size greater than the first size andmay overlap horizontally with a portion of a metallic feature in thefirst metal layer to obstruct light incident on a first side of the PCBfrom transmission to a second side of the PCB through a region of thePCB substrate near the via. Like the first metal layer, the second metallayer may also include a plurality of other metallic features necessaryto implement the desired electrical connectivity of the PCB.

In block 808, the via may be created. The via may electrically connectthe first catch pad to the second catch pad, thereby providing anelectrical connection between the first and second metal layers of thePCB. The via may be created by drilling through a portion (e.g., centerportion) of each of the first and second catch pads of the PCB.Photoresist may be applied, exposed through a mask, and developed toprotect all regions where metal deposition is not desired. Thus, thebarrel (i.e., bore) of the via may be left unprotected and metal may bedeposited along the barrel to electrically connect the first and secondcatch pads. The volume of the via may then be filled with metal orfilled with a nonconductive material and plated over by a metal layer(e.g., via in pad). The volume of the via may be filled or plated overto prevent transmission of light between the two sides of the PCB by wayof the via.

In some instances, the entire via may be drilled and filled in one step(e.g., a through-hole via). Alternatively, the via may be drilled andfilled in multiple steps. A stacked microvia, for example, may be builtup sequentially by fabricating a portion of the stacked microvia eachtime a metal layer is created on the PCB substrate. Specifically, theoperations of laser drilling, metal deposition, and filling of the viamay be repeated for each metal layer to build up the microvia stack.

A multilayer PCB may be manufactured by providing additional PCBsubstrate layers and depositing additional metal layers thereon. Theadditional metal layers may include catch pads of the first size, thesecond size, or another larger or smaller size, as needed to obstructtransmission of light through regions of the PCB substrate around thevia. Additionally, other known PCB manufacturing techniques may be usedin addition to or instead of the techniques herein described in order tocreate the PCB layers and features therein. The manufacturing processesused may depend on the type of via desired or the size of the PCBcomponents, among other factors.

VII. Conclusion

The present disclosure is not to be limited in terms of the particularembodiments described in this application, which are intended asillustrations of various aspects. Many modifications and variations canbe made without departing from its scope, as will be apparent to thoseskilled in the art. Functionally equivalent methods and apparatuseswithin the scope of the disclosure, in addition to those enumeratedherein, will be apparent to those skilled in the art from the foregoingdescriptions. Such modifications and variations are intended to fallwithin the scope of the appended claims.

The above detailed description describes various features and functionsof the disclosed systems, devices, and methods with reference to theaccompanying figures. The example embodiments described herein and inthe figures are not meant to be limiting. Other embodiments can beutilized, and other changes can be made, without departing from thespirit or scope of the subject matter presented herein. It will bereadily understood that the aspects of the present disclosure, asgenerally described herein, and illustrated in the figures, can bearranged, substituted, combined, separated, and designed in a widevariety of different configurations, all of which are explicitlycontemplated herein.

A block that represents a processing of information may correspond tocircuitry that can be configured to perform the specific logicalfunctions of a herein-described method or technique. Alternatively oradditionally, a block that represents a processing of information maycorrespond to a module, a segment, or a portion of program code(including related data). The program code may include one or moreinstructions executable by a processor for implementing specific logicalfunctions or actions in the method or technique. The program code and/orrelated data may be stored on any type of computer readable medium suchas a storage device including a disk or hard drive or other storagemedium.

The computer readable medium may also include non-transitory computerreadable media such as computer-readable media that stores data forshort periods of time like register memory, processor cache, and randomaccess memory (RAM). The computer readable media may also includenon-transitory computer readable media that stores program code and/ordata for longer periods of time, such as secondary or persistent longterm storage, like read only memory (ROM), optical or magnetic disks,compact-disc read only memory (CD-ROM), for example. The computerreadable media may also be any other volatile or non-volatile storagesystems. A computer readable medium may be considered a computerreadable storage medium, for example, or a tangible storage device.

Moreover, a block that represents one or more information transmissionsmay correspond to information transmissions between software and/orhardware modules in the same physical device. However, other informationtransmissions may be between software modules and/or hardware modules indifferent physical devices.

The particular arrangements shown in the figures should not be viewed aslimiting. It should be understood that other embodiments can includemore or less of each element shown in a given figure. Further, some ofthe illustrated elements can be combined or omitted. Yet further, anexample embodiment can include elements that are not illustrated in thefigures.

Additionally, any enumeration of elements, blocks, or steps in thisspecification or the claims is for purposes of clarity. Thus, suchenumeration should not be interpreted to require or imply that theseelements, blocks, or steps adhere to a particular arrangement or arecarried out in a particular order.

While various aspects and embodiments have been disclosed herein, otheraspects and embodiments will be apparent to those skilled in the art.The various aspects and embodiments disclosed herein are for purposes ofillustration and are not intended to be limiting, with the true scopebeing indicated by the following claims.

What is claimed is:
 1. A light detection and ranging (LIDAR) systemcomprising: a housing comprising an aperture; a printed circuit board(PCB) including a first side and a second side and disposed within thehousing; a light sensor connected to the second side of the PCB,disposed within the housing, and configured to sense light incident onthe light sensor through the aperture; and an optically isolatinginterface formed between the PCB and at least part of the housing,wherein the PCB comprises: a first metal layer comprising a firstplurality of metallic features that includes a first via catch pad; anda second metal layer comprising a second plurality of metallic featuresthat includes a second via catch pad, wherein a particular metallicfeature of the second plurality of metallic features overlapshorizontally with corresponding one or more metallic features of thefirst plurality of metallic features, and wherein, by overlappinghorizontally with the corresponding one or more metallic features of thefirst plurality of metallic features, the particular metallic featureand the corresponding one or more metallic features are configured toobstruct light incident on the first side of the PCB from transmissionthrough corresponding dielectric material regions of the PCB to thelight sensor.
 2. The LIDAR system of claim 1, wherein the firstplurality of metallic features and the second plurality of metallicfeatures are arranged such that, at all points along a horizontal areaof the PCB, at least one metal layer contains a metallic feature thatobstructs light from transmission through corresponding dielectricmaterial regions of the PCB.
 3. The LIDAR system of claim 1, wherein thecorresponding one or more metallic features create a continuoushorizontal overlap with an outer boundary of the particular metallicfeature.
 4. The LIDAR system of claim 1, wherein the PCB furthercomprises a third metal layer comprising a third plurality of metallicfeatures, and wherein the first plurality of metallic features and thethird plurality of metallic features create a continuous horizontaloverlap with an outer boundary of the particular metallic feature. 5.The LIDAR system of claim 1, each respective metallic feature of thesecond plurality of metallic features overlaps horizontally withcorresponding one or more metallic features of the first plurality ofmetallic features, and wherein, by overlapping horizontally with thecorresponding one or more metallic features of the first plurality ofmetallic features, the respective metallic feature and the correspondingone or more metallic features are configured to obstruct light incidenton the first side of the PCB from transmission through correspondingdielectric material regions of the PCB to the light sensor.
 6. The LIDARsystem of claim 1, wherein the horizontal overlap between the particularmetallic feature and the corresponding one or more metallic features isassociated with at least a minimum number of reflections of a photonsuch that the photon is, prior to transmission of the photon through thePCB, reflected out of the PCB or absorbed by metallic features of thePCB.
 7. The LIDAR system of claim 1, wherein the PCB comprises: a viaextending between the first metal layer and the second metal layer andconnected to the first via catch pad and the second via catch pad,wherein the first via catch pad has a first size, and wherein the secondvia catch pad has a second size greater than the first size.
 8. TheLIDAR system of claim 7, wherein the particular metallic featurecomprises the second via catch pad, and wherein the corresponding one ormore metallic features with which the second via catch pad overlapshorizontally comprise at least one metallic feature different from thefirst via catch pad and located in a different horizontal position thanthe first via catch pad.
 9. The LIDAR system of claim 1, wherein thehousing comprises an enclosure connected to the PCB, wherein the lightsensor is disposed within the enclosure, and wherein the aperture isdefined at least in part by the enclosure.
 10. The LIDAR system of claim1, wherein the light sensor comprises a single-photon light sensor. 11.The LIDAR system of claim 1, wherein the optically isolating interfaceis formed by a gasket disposed between the second side of the PCB andthe at least part of the housing.
 12. An apparatus comprising: anenclosure comprising an aperture; an integrated circuit (IC) deviceincluding a first side and a second side and disposed within theenclosure; a light sensor connected to the second side of the IC device,disposed within the enclosure, and configured to sense light incident onthe light sensor through the aperture; and an optically isolatinginterface formed between the IC device and at least part of theenclosure, wherein the IC device comprises: a first metal layercomprising a first plurality of metallic features that includes a firstvia catch pad; and a second metal layer comprising a second plurality ofmetallic features that includes a second via catch pad, wherein aparticular metallic feature of the second plurality of metallic featuresoverlaps horizontally with corresponding one or more metallic featuresof the first plurality of metallic features, and wherein, by overlappinghorizontally with the corresponding one or more metallic features of thefirst plurality of metallic features, the particular metallic featureand the corresponding one or more metallic features are configured toobstruct light incident on the first side of the IC device fromtransmission through corresponding optically-transmissive regions of theIC device to the light sensor.
 13. The apparatus of claim 12, whereinthe first plurality of metallic features and the second plurality ofmetallic features are arranged such that, at all points along ahorizontal area of the IC device, at least one metal layer contains ametallic feature that obstructs light from transmission throughcorresponding optically-transmissive regions of the IC device.
 14. Theapparatus of claim 12, wherein the corresponding one or more metallicfeatures create a continuous horizontal overlap with an outer boundaryof the particular metallic feature.
 15. The apparatus of claim 12,wherein the IC device further comprises a third metal layer comprising athird plurality of metallic features, and wherein the first plurality ofmetallic features and the third plurality of metallic features create acontinuous horizontal overlap with an outer boundary of the particularmetallic feature.
 16. The apparatus of claim 12, wherein the IC devicecomprises: a via extending between the first metal layer and the secondmetal layer and connected to the first via catch pad and the second viacatch pad, wherein the first via catch pad has a first size, and whereinthe second via catch pad has a second size greater than the first size.17. The apparatus of claim 16, wherein the particular metallic featurecomprises the second via catch pad, and wherein the corresponding one ormore metallic features with which the second via catch pad overlapshorizontally comprise at least one metallic feature different from thefirst via catch pad and located in a different horizontal position thanthe first via catch pad.
 18. The apparatus of claim 12, wherein theoptically isolating interface is formed by a gasket disposed between thesecond side of the IC device and the at least part of the enclosure. 19.A vehicle system comprising: a housing comprising an aperture; a printedcircuit board (PCB) including a first side and a second side anddisposed within the housing; a light sensor connected to the second sideof the PCB, disposed within the housing, and configured to sense lightincident on the light sensor through the aperture; a processorconfigured to control the vehicle system based on signals generated bythe light sensor; and an optically isolating interface formed betweenthe PCB and at least part of the housing, wherein the PCB comprises: afirst metal layer comprising a first plurality of metallic features thatincludes a first via catch pad; and a second metal layer comprising asecond plurality of metallic features that includes a second via catchpad, wherein a particular metallic feature of the second plurality ofmetallic features overlaps horizontally with corresponding one or moremetallic features of the first plurality of metallic features, andwherein, by overlapping horizontally with the corresponding one or moremetallic features of the first plurality of metallic features, theparticular metallic feature and the corresponding one or more metallicfeatures are configured to obstruct light incident on the first side ofthe PCB from transmission through corresponding dielectric materialregions of the PCB to the light sensor.
 20. The vehicle system of claim19, wherein the housing comprises an enclosure connected to the PCB,wherein the light sensor is disposed within the enclosure, and whereinthe aperture is defined at least in part by the enclosure.